Diagnostic and clinical significance of KIT(CD117) expression in thymic epithelial tumors in China

Aims: To study KIT (CD117) expression in thymic epithelial tumors in China, and investigate diagnosticand clinical significance. Material and Methods: Thymic epithelial tumors (TETs) from 102 patients (3 type A,29 type AB, 5 type B1, 22 type B2, 29 typeB3 and 16 thymic carcinomas) were examined. Immunohistochemicalstaining with an antic-kit monoclonal antibody was performed on a tissue microarray. Relationships betweenKIT positive expression and the TET clinical characteristics (WHO histologic classification and Masaoka stagesystem) were analysed. Results: The KIT positive expression rate was significantly higher in thymic carcinoma(60%, 9/16) than in thymoma (8%, 7/86), a strong correlation being found with the WHO classification, but notthe Masaoka tumor stage. The overall survival for patients with KIT positive lesions was significantly worse.Conclusions: KIT is a good molecule marker to differentially diagnose thymic carcinoma from thymoma, whilealso serving as a predictor of prognosis for TETs. Further research into KIT mutations in Chinese TETs shouldbe conducted to assess the efficacy of targeted therapy.